The present invention relates to the improvement of methods for testing articles made of superhard materials, and more particularly is concerned with a method for testing wear resistance of articles on the basis of polycrystalline cubic boron nitride and may be the most efficiently used in rejecting blanks for the manufacture of cutting tools.
The wear resistance of a tool is characterized by the value of h.sub.z of a trailing edge of a tool in millimeters under predetermined machining conditions during a predetermined time period, and the greater the wear h.sub.z, the lower wear resistance. The term "the lowest admissible wear resistance value" means herein that wear resistance which ensures a predetermined productivity with a predetermined accuracy class and surface finish.
Methods for testing wear resistance of articles heretofore known are based upon mechanical destruction (abrasion) of a part of the article and measurement of the amount of wear which characterizes the wear resistance. The most reliable results are obtained by performing test turning using for that purpose the tools made of the articles being tested. In this case the turning is by means of turning tools under conditions most similar to the operating conditions which will be met by the articles. The amount (h.sub.z) measuring the tool wear over the trailing edge thereof is used as a value for characterizing the wear resistance of the article.
The disadvantages of known methods consist in that they permit evaluation of the wear resistance for only a portion of the article, under test and not for the article as a whole. Also reproduction of the test results is not possible and the known methods are rather labour-consuming.
In addition, it should be noted that the above-described method is the destructive method and is selective since testing of the wear resistance of only a sample of the tested number of articles is possible.
Therefore, the above described known methods do not provide a reliable test of articles which eliminates the possibility of subgrade articles being shipped to a purchaser.